The invention relates to a magnetic bearing arrangement, particularly a bearing arrangement for a high-speed rotor. Such an arrangement may include two magnetic bearings which provide an axial tensioning force on the rotor, and with substantially coaxial construction of component parts provided respectively on rotor or stator they cause a passive stabilization in a radial direction. The rotor axis is preferable vertical.
Such a magnetic bearing arrangement is known from U.S. Pat. No. 3,473,852 in which two actively controlled, electromagnetic bearings are provided for axial stabilization of the rotor. These magnetic bearings include electromagnets with pole rings arranged on the stator, and ferromagnetic pole rings lying on the rotor adjacent to them. Because of the coaxial construction of the pole rings of rotor and stator, an uncontrolled passive stabilization is also achieved. The rigidity of this arrangement is however comparatively low in a radial direction or about axes perpendicular to the axis of rotation of the rotor, so that, when correspondingly loaded and, for example, resonant oscillations which occur when passing through critical rotary speed ranges may not be taken up by the magnetic bearing arrangement. Therefore, magnetic bearing arrangements have been proposed -- for example in U.S. Pat. No. 3,650,581 -- in order to provide actively controlled magnetic bearing systems for the axis of freedom. Such an arrangement is, however, very expensive in construction and manufacture and also requires considerable energy for producing the necessary bearing forces in all directions.
The invention seeks to reduce or avoid the above disadvantages and to create a magnetic bearing arrangement which is simple in construction and of favourable cost, which can ensure a suitably stable behavior of the rotor over all its intended rotational speed ranges. Moreover, the magnetic bearing arrangement is intended to be particularly applicable to vacuum technology, wherein, above all, electrical ducts, seals and the like should be avoided on the vacuum side.